Chaeles stanley rhoads



C. S. RHOADS, 1n.

TELEPHONE SYSTEM.

APPLICATION HLED mums, 1911.

-1,324,746. Patented Dec. 9, 1919.

CHARLES sTANLEY nrronns, .13., 0F INDIANAPOLIS, INDIANA.

' TELEPHONE sYsTEM.

j Specification of'L etters Patent.

' Patented-Dec. 9, 1919.

Application filed June as, 1917; semi No. 177,437.

To all whom it may concern:

Be it known that I, CHARLES STANLEY Rnoans, J12, a citizen of the United States, residing at Indianapolis, in the county of Marion and State of Indiana, have invented a certain new and useful Improvement in Telephone Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone systems and more particularly to systems of the kind used for telephone train despatching in which a great many telephone substations are adapted for simultaneous connection to a single circuit. Circuits such as these may be all the way from one hundred to two hundred and fifty miles in length and in a great many cases are constructed of iron wire. .This indicates the difiiculties presented to the attempt to secure adequate transmission thereover.

In accordance with my invention I provide a receiver circuit at each substation having a Very high resistance. In the preferred form of the invention I utilize a reoeiver having about fifteen hundred ohms of resistance, and this receiver I bridge directly across the line circuit. I have found that by using a receiver of this kind I am enabled to obtain satisfactory speech transmission over lines such as hereinbefore referred to.

I will describe one form which my invention may take more in detail by referring to the accompanying drawing illustrating a line circuit having various forms of substation circuits.

In this drawing I show a pair of line wires 1 and 2 as uniting substations A, B, C, D and E. I have shown at station A a transmitter 3 which together with the battery 4 and primary winding 5 forms the local circuit controlled by the switch lever 6. This switch lever 6 is conjointly operated with the switch 9 of fifteen-hundred ohms resistance is alone in bridge of the line wires at this particular station.

With receivers of this resistance and with the circuit thus arranged I am enabled to carry on satisfactorily conversation over relatlvely poor line circuits even though a very large number of receiver bridges are included in this separate bridge a condenser 11. The general plan however is of course the same as illustrated for the substation A.

' At the substation O I show a structure similarto that indicated at substation A except that I insert an impedance coil 12 having a movable enveloping iron shell 13,

which shell by its movement may increase or decrease the impedance offered by thecoil 12.

At the substation D I place a receiver 9 in a local secondary circuit by including it in series with a secondary 13, the primary 14 whereof occupies the position in the bridge circuit occupied by the receiver in the stations A and B.

At substation E I provide an auto-transformer coil 15 across allor part of whose turns the receiver 9" is bridged,there being preferably included a. coil 16 in circuitwith said receiver. 7 r

At the substations D and 15 respectively provide the high resistance Or impedance necessary, the receivers 9 under those conditions being high or low wound asmay best suit the requirements of the secondary circuit. F

In using the words high resistance n the claim I means a resistance of substantially fifteen hundred ohms, or thereabout.

From what has been thus described the nature. of my invention will be clear to those skilled in the art. f

'What I claim as my invention is:

A long distance telephone transmission system having a plurality of substations all united by a common line circuit, each substation having a transmitter, a battery there for, and a primary winding of an induction coil included in a local circuit, a high resistance receiver circuit includin a re,- ceiver at each of said substations, said high and E-the coils p 4 resistance receiver circuit including an autotransformer together with a bridge about said auto-transformer including a receiver and a high resistance, connected 1n a bridge across said line circuit, a secondary winding for the induction coil inductively associated With said primary Winding and adapted for connection in bridge of said receiver, and manually operable means for conjointly controlling the simultaneous closure and rupture of said local circuit and the circuit in- 10 eluding said secondary Winding.

In witness whereof, I hereunto subscribe my name this 12th day of May, A. D., 1917.

CHARLES STANLEY RHOADS, JR. Witness:

H. F. STEVENSON. 

